Conventionally, hoses having a rubber layer formed using a rubber composition having flame retardancy have been proposed.
For example, Japanese Unexamined Patent Application Publication No. 2013-129684 discloses a rubber composition for a hose including chloroprene rubber, butadiene rubber, and styrene-butadiene rubber as rubber components, from 60 to 80 parts by mass of the chloroprene rubber, and from 5 to 25 parts by mass of silica per 100 parts by mass of the rubber components.
When the present inventors prepared and evaluated rubber compositions containing chloroprene rubber, styrene-butadiene rubber, and butadiene rubber according to Japanese Unexamined Patent Application Publication No. 2013-129684, they found that such rubber compositions sometimes have low flame retardancy.